NGDC Marine Trackline Geophysics Database

This data set contains bathymetry, magnetic, gravity and seismic shot point navigation
data collected during marine cruises from 1939 to the present. Coverage is worldwide.
These data are stored in the MGD77 exchange format and are available for download
in a variety of user selectable formats. One Header record and multiple Data records
are available for a particular cruise/leg (port to port operation). The Header record
documents both the content and the structure of the subsequent Data records, containing
that part of the data that remains invariant throughout the cruise. The Data records
present geophysical data (bathymetry, magnetics and gravity) and seismic information
(shot-point identification) with a corresponding time and position. Documentation
that varies within the cruise is also included with the data records. Data are fully
searchable on-line by geographic area, year of cruise, institution, platform, cruise,
date or data type.

While every effort has been made to ensure that these data are accurate and reliable
within the limits of the current state of the art, NOAA cannot assume liability for
any damages caused by any errors or omissions in the data, nor as a result of the
failure of the data to function on a particular system. NOAA makes no warranty, expressed
or implied, nor does the fact of distribution constitute such a warranty.

Not to be used for navigation. Although these data are of high quality and useful
for planning and modeling purposes, they are not suitable for navigation. For navigation,
please refer to the NOS nautical chart series.